Africa is dominated by deserts...
...from the Kalahari in the south to the mighty Sahara in the north.
These are fascinating worlds...
each one unique... all a challenge...
Yet life can conquer them... and in the most surprising ways.
This is an epic journey across Africa's magnificent deserts,
a story of survival against the odds.
Africa.
Seen from space, great swathes of sand and rock
cover more than half the continent.
In the far south, bordering the Atlantic,
is the world's most ancient desert the Namib.
For 80 million years, cold dry winds have swept in from the ocean,
denying the land moisture and piling enormous sand dunes against the shore...
Beautiful but impossibly dry,
in a good year the Namib gets just five centimetres of rain...
in a bad year, it rains only sand.
But buried within the dunes, there is treasure.
Fragments of dead animals and plants,
swallowed long ago by the sand,
are swept to the surface... offering a crucial lifeline...
Beetles - many different species
have found ways to harvest this bounty.
Along with termites and lizards,
they're the foundations for a delicate chain of life in the Namib.
In this barren sea of sand,
it's harder for larger animals to find enough to eat.
You've got to be a real specialist... like the Namib sand snake.
By sidewinding, it can "swim" its way up the dunes.
But in such an open arena, ambush is tricky...
it's speed that counts...
The wedge-snouted lizard can afford to be blase...
it has a secret weapon...
...rocket propulsion.
Then it's under the sand as fast as you can...
the best place to escape predators and the sun.
Here in the Namib shelter is sparse...
what little there is, is fiercely protected.
Colonies of dune ants monopolise the tough Namib grasses.
Though aggressive to most invaders,
the ants do tolerate the presence of small sap-sucking bugs
which they get to milk for precious sugary water...
In their grassy home the ants are shaded from the worst of the sun,
but out on the surface of the sand
the temperature can reach a blistering 60 Celsius.
Spoor spiders have an extraordinary survival strategy.
With nowhere to hang their webs,
they spin their silk on the ground, meshing sand grains together.
The result: A mini-blanket which serves as a sunscreen.
But these sandy blankets do more than shelter.
They're beautifully-camouflaged, sticky traps.
Dune ants get most of the food they need on their doorstep,
but to supplement their diet they must also venture out onto the sand.
Their long legs lift them above the baking ground...
to where the temperature is slightly cooler.
But they must still tread carefully... it's a minefield out there.
Pinning the ants to the hot sand surface,
the spiders first cook them to death before dragging them under.
In the Namib even the toughest animals struggle with the heat.
Gemsbok trek to the crests of the highest dunes
to seek relief in the breeze.
With no cloud cover,
solar radiation blasting the desert is intense.
The mid-day sand is so hot it's like a bed of burning coals...
The Namib quickstep... over millions of years,
you learn to keep your claws cool...
Pushed by the wind, the dunes avalanche...
The Namib's residents can't fight the tide...
Though the dunes are unstable,
they provide a home for a remarkable creature.
The trapdoor spider only builds its nest on the top of the steepest dunes...
It's learned to do this because it has a very aggressive enemy.
...a wasp which relentlessly scours the sand.
Though its eyesight is poor,
the wasp has very sensitive hairs on its legs,
which can pick up the slightest scent of a spider.
When it finds a nest the wasp quickly works out
how deep the burrow is.
If it's shallow the wasp starts digging... for up to two hours.
It's hard work against the slipping sand.
With the spider exposed,
it's now a battle between the wasp's paralysing sting and the spider's jaws.
But the wasp has quicker reflexes.
Cornered, the spider now plays its trump card.
Hurling itself down the dune, it flips into a wheel.
Travelling at over 40 turns a second, it makes a dizzy dash for freedom.
Safe at last.
Back up the dune the wasp is left standing,
chasing the scent of his vanished meal.
Instinct, honed over time,
governs much of the life in the Namib,
but some creatures also have to learn how to conquer these sands,
using knowledge passed down over generations.
African elephants are so resourceful they can survive even here,
in the heart of the desert.
Elephants have remarkable powers of memory.
Though this desert is more than 2 million square kilometres in size,
the hundred or so elephants it supports
know precisely where to find enough to eat and drink.
It takes a lot of food up to three hundred kilos a day
to feed the world's largest land animal...
and all of that from a desert...
But there's one plant here - the Nara
whose roots draw water from deep underground
each year it produces a bumper crop of melons.
Elephants just love them.
Each melon is a valuable package of moisture and seeds.
The plant also benefits from this plunder
as its seeds may be carried for 50 kilometres
in the elephant's stomach,
before being dropped in a pile of fertilising dung.
But the Nara needs more than a passing trade
with elephants to spread its seeds.
Under the cover of darkness,
the nutritious melons also pull in the locals,
like Cape porcupines.
Porcupines may wander up to 15 kilometres a night in search of ripe melons.
They rely on a sharp sense of smell.
Nara melons have a tough outer shell,
but the porcupine's large incisors make short work of them.
Like elephants, porcupines help the Nara to spread its seeds.
By opening up fruits, they also create opportunities for other dune creatures.
Hairy-footed gerbils are hot on their heels.
In the cool of the desert night these little rodents
burn up energy quickly and so must gather food fast...
Though plentiful, the Nara seeds take some plucking...
The gerbils provision for leaner times ahead
but they must also keep alert.
Cape foxes patrol the Nara bushes, looking for gerbils.
Surprisingly the foxes are also partial to the thirst-quenching melons.
But there is a great mystery here.
This is the most extreme African environment...
it may not rain for ten years at a stretch...
so how does the Namib support so much life?
On certain nights the secret is revealed.
Warm, damp air, moving in from the mid-Atlantic
is transformed to fog as it crosses the cold coastal current.
A vast blanket of moisture steadily rolls across the desert.
This veil of mist is the saving grace of the Namib.
Just a few precious drops but enough to allow life to flourish.
A tiny bit of moisture,
a tiny bit of food and tens of millions of years of evolution
are the secrets to success in this harshest of African deserts.
Where else but the Namib would an ingenious little beetle stagger up
the highest dunes on cold mornings,
put its back to the breeze and then stand on its head,
to collect a life-giving drink?
Lmpressive sand dunes dominate the Namib,
but to the south and east is a very different kind of desert
an expanse rocky scrub known as the Karoo.
This desert is as old as the Namib, but here it is mainly rain,
not fog, that drives life.
In the Karoo up to 30 centimetres of rain may fall during winter...
and this extra sprinkle of moisture makes the world of difference.
In spring the desert undergoes a remarkable transformation.
For just a few weeks a year,
the flowers of over 3000 different plant species
turn this desert into the Garden of Africa.
This dazzling variety of colour has evolved over time
for a very special purpose
for plants to seduce their insect pollinators.
Some extraordinary relationships have been forged...
The bright purple blossoms of Lapeirousia
are designed purely to attract a fly with the longest tongue in Africa.
As the fly probes for a sip of nectar in the long floral tubes,
pollen is dabbed onto its forehead.
A smart design...
but on a windy day it's not so easy to hit the target.
Diascia flowers use not nectar but nutritious oils
secreted by glands at the tips of their floral tubes
to tempt pollinators.
Flower and bee in this case a perfect fit
as the insect dips its toes for oil.
Ignited by the rain the flowering of the Karoo touches
the lives of all its inhabitants.
Brandt's whistling rats are quick
to harvest the blossoms around their burrows.
These desert rats time their breeding to the burst of fresh food...
but with snakes around,
mothers can't risk leaving their youngsters at home.
Clinging to her nipples,
they're carried along... a sort of... meals on wheels!
Within a month the spring blooms are finished.
The plants now set their seeds,
taking advantage of the warm summer winds which sweep the desert.
For a while, the Karoo just glows.
But trouble is stirring...
Triggered by the rains, an all-devouring army: Locusts.
Millions emerge from eggs buried in the sand...
gathering into columns which may stretch for 10 kilometres.
At this stage they can't fly - only hop but it doesn't hinder their progress.
These sweeping hordes devastate any fresh growth in their path.
After five weeks of steady munching, the infantry becomes airborne.
These breeding swarms can cover up to 80 kilometres a day...
but only while the food and moisture last.
So how do you define a desert in Africa?
They're places where less than fifty centimetres of rain falls a year.
Neighbouring the Karoo is a desert which gets the maximum - in brief,
but intense summer monsoons.
It's the wettest of all African deserts the great Kalahari.
The sands of the Kalahari cover more of southern Africa than any other desert.
But the higher rainfall here gives it a very distinctive appearance:
More like a savannah,
its sandy ridges carpeted with grasses and a scattering of trees.
In the wet season the Kalahari sands are loosened by the rain,
making them easier to excavate.
Damara molerats, which spend their lives underground,
are now at their most active, hunting for roots and bulbs.
But digging takes 1000 times more energy than travelling on the surface...
...and even in this greenest of African deserts
the bulbs can be widely spread.
Living on its own, a single molerat would never find enough to eat,
so these small rodents have evolved a co-operative lifestyle,
with up to 40 family members working together.
Like ants or bees, only the queen molerat breeds,
and all her workers are sterile females.
But everybody will benefit
from the extra mouths who'll eventually join in the hunt for food.
Damara molerats are unusual in that their lips
are actually behind their front teeth.
It helps them to avoid swallowing sand while digging.
But it also stops them drinking,
so they must extract all the moisture they need from the bulbs.
During the wet season the bulbs are gathered quickly
before they germinate and lose their goodness.
The molerats store them in special larders
as insurance against the dry months ahead.
Living underground,
molerats are sheltered from the Kalahari's worst extremes of temperature.
We think of deserts as hot places,
but nightly temperatures can fall well below zero.
At dawn meerkats need to soak up
the warmth of the rising sun to get fully active.
The temperature in the Kalahari steadily climbs...
as high as 70 Celsius on the ground.
Meerkats can only tolerate short bursts of activity in the morning and evening.
This means they need to be very efficient at gathering food...
so they quarter their territory, travelling several kilometres a day.
Tasty beetles and scorpions are common in this grassy desert.
But finding them means spending a lot of time
with your head in the sand...
so meerkats are very vulnerable to predators.
To protect the group young males take turns keeping watch.
This frees the others up to keep hunting.
Scorpions have a lethal sting, but meerkats are fast as lightning.
The Kalahari's high levels of rainfall mean food is plentiful year-round...
one reason why this desert can support
more large mammals than any other in the world.
Springbok are the most successful desert antelopes in Africa.
With short thin fur they can easily offload heat by sweating...
the white patterns on their coats help to reflect solar radiation.
And they never need to drink.
They can extract all the moisture they need
from the most meagre desert plants.
But in southern Africa's deserts, there is a lurking challenge.
Cheetahs shadow the springbok herds.
They, too, evolved in the desert.
Thinly-furred and lightly-built,
everything about them is designed to deal with heat and speed.
Cheetahs are sprinters not made for a long distance chase.
So they must get close.
But springbok have keen senses.
True to their name, springbok can leap two metres high.
It's jumping with a purpose:
It signals a warning to the others and confuses attackers.
After such a burst of activity, springbok need to cool down fast.
Here in the Kalahari temperatures can be unbearable,
but large animals can at least find a shady haven
under the broad canopies of camelthorn trees.
For ground squirrels, it's also time to seek shade.
The sand is much cooler just beneath the surface,
so each squirrel digs its own special trench.
For most Kalahari mammals mid-day is siesta time a chance to unwind.
Even the meerkat sentry takes his eye off the job...
But a sociable weaver's work is never done.
They're busy, constructing their own unique shelter.
These giant haystacks can accommodate up to 300 individuals
and can weigh over a tonne.
Because they're occupied year-round, thatching is an endless task.
The nests are a miracle of home-made air conditioning.
Air trapped in the pockets of the thatch acts
as a buffer against extremes of temperature.
In summer it can be 10 degrees Celsius cooler inside.
Teamwork has helped the weavers find a neat solution
to the problems posed by the Kalahari sun.
But some creatures are even better equipped.
Ground squirrels have ready-made parasols.
Under the shadow of their fluffy tails,
they can resume foraging while the sun is still high in the sky.
But the trouble with being active at this time of day
is that so are cold-blooded animals... like the Cape cobra.
Ground squirrels have such quick reflexes they're in no real danger.
But they're still anxious to be rid of it.
They now use their bushy tails to intimidate and frustrate the snake
rather like a red rag to a bull.
It's all too much for the cobra.
Better to just slip away quietly.
As evening draws in, temperatures in the Kalahari can plummet.
Sociable weavers retreat to their insulated nest chambers...
and by snuggling together can sleep,
warm and comfortable, through the night.
Small mammals, like ground squirrels and meerkats,
return to the safety and warmth of their burrows.
Time now to lie low, prepare the warren and bond.
Today, despite its extreme temperatures,
the Kalahari is Africa's mildest desert.
But this hasn't always been so.
Over the last 15 million years Africa's climate
has repeatedly swung from wet to dry and back again
as Ice Ages have come and gone.
At times the Kalahari has been much drier than it is today...
it's sands stretching as far as the equator...
linking it with the largest desert in the world...
the Sahara.
Covering 9 million square kilometres,
the Sahara is so vast the whole of Australia
could comfortably fit into it.
It is bleak... inhospitable... and...
compared to southern Africa's deserts... very new.
Few animals have had time to get to grips with this mighty wilderness...
a place where only the hardiest can get by.
Scimitar-horned oryx are true desert nomads,
wandering for hundreds of miles across the Sahara in search of sparse shrubs.
They've lived long enough in other,
dry regions of Africa to tackle the hardships of this fierce young desert.
Oryx are unusual among antelopes in that females have horns as long as males.
They use these formidable weapons to aggressively deter outsiders
from joining their group, especially when food is limited.
Scimitar-horned oryx are among a handful of tough African mammals
able to cope with the Sahara.
Only one other creature is tougher.
The Arabian camel - not even a native
was domesticated in the deserts of Asia
and brought to North Africa as a means of transport.
In the past, Tuareg nomads used camels to move slaves,
gold and ivory between West Africa and the Mediterranean.
Today their caravans still trade... in salt, dates and millet.
The Sahara has long been a frontier between Asia and Africa.
But there are European pioneers here too red foxes
which scrape a living on the northern fringes of this vast desert.
Though much of the Sahara is uninhabitable,
there are a few special places where life can thrive.
The Ennedi mountains in Tchad harness a little more moisture
from clouds than lower-lying areas
enough to support tiny pockets of savannah.
Here, rock hyraxes survive on the leaves of acacia trees
a scene more typical of the African plains.
These green islands are relics of an older world,
one which is slowly vanishing with the march of the desert sands.
The Sahara as we know it today is only 2000 years old...
the product of a rapidly drying climate in North Africa.
But our ancestors also had a hand in this change...
by over-cultivating marginal lands and intensively grazing livestock.
Before, things were very different.
Try to imagine this land flooded by the ocean,
swathed in forest and savannah... swept by mighty rivers.
Ennedi gorge once fed a vast tributary of the Nile.
Today all that remains are a few precious pools
crucial watering holes for passing caravans of camels.
In just ten minutes of drinking these remarkable animals
can put on a third of their body weight in water...
It's enough to carry them for well over a hundred kilometres to the next oasis.
Arabian camels and nomadic people are the most recent
in a long line of Saharan pioneers.
The history of this great region is told in ancient rock art
glimpses of a vanished world.
Just a few thousand years ago this desert was still wet
enough to support great herds of cattle and goats.
Prey was abundant, and people used horse-drawn chariots, dogs,
bows and arrows in the hunt for food.
Giraffes, elephants, buffalo, lions and rhino roamed across the Sahara.
There were rivers full of fish...
...even crocodiles.
Today at Ennedi gorge, there are living reminders of that once green Sahara.
In a few isolated oases,
there's still an abundance of aquatic life.
Even more surprising,
is that these communities of fish still
support a dwindling number of Nile crocodiles.
They are the last survivors of a once-healthy population which
over thousands of years
has been left high and dry by the changing climate.
Today just three crocodiles remain too few to continue the line
marooned by hundreds of miles of sand
right in the middle of the mightiest desert on earth.
Africa's deserts are more than just barren expanses...
they're dynamic worlds...
each with its own, unique character...
They are also places of great opportunity...
where given enough time,
a steady climate and a sprinkle of water...
life can flourish.
And it has done so...
in some of the most extraordinary ways imaginable.